1. Field of the Invention
The invention relates to a new compound N-[3- [2-(1H-imidazol-1-yl)ethoxy]phenyl]-4-(2-thienyl)-2-pyrimidinamine and its pharmacologically acceptable salts which exhibit unexpected advantageous bioavailability properties as evidenced by increased plasma half life and to their use in the treatment of asthma and allergic diseases. 2. Description of the Prior Art
The bronchospasm of allergic asthma is a consequence of the release of mediators, such as histamine and slow-reacting substances from mast cells. Certain 4, 5, 6-Substituted-N-(substituted phenyl)-2-pyrimidinamines having antiasthmatic activity are disclosed in U.S. Pat. Nos. 4,788,195 and 4,876,252. While the compounds disclosed and synthesized therein are highly active as antiasthmatic and antiallergic agents in several test systems; it is very difficult to predict from those test systems which compound will exhibit sufficient bioavailability to demonstrate the desired anti-asthmatic and anti-allergic pharmacological effects reproducibly and over sustained periods. As it is generally known and accepted that drug activity is correlated with drug plasma concentrations, the effective treatment of asthma is best achieved by an active compound which exhibits enhanced bioavailability as demonstrated by a prolonged residence in plasma at efficacious concentrations. There is a great need for efficacious compounds to be used in the treatment of asthma and having sufficient bioavailability to produce repeatable and long lasting plasma levels in patients.